This invention relates to a method of forming a porous body of molybdenum, molybdenum alloy, tungsten, or tungsten alloy.
A method for forming porous ceramic structures is disclosed in U.S. Pat. No. 3,833,386. An isocyanate capped polyoxyethylene polyol is reacted with large amounts of an aqueous slurry of sinterable ceramic material. A hydrophilic crosslinked polyurethane foam is generated having sinterable material uniformly disposed throughout. The foamed structure is heated in an atmosphere of air, oxygen, inert gases or the like to decompose the polyurethane and sinter the remaining sinterable ceramic material forming a rigid ceramic foam structure. In addition, it is disclosed that metal systems such as aluminum powder, or nickel powder along with a binder, fluxing agent and a liquid carrier can be reacted with the isocyanate capped polyoxyethylene polyol to form the foamed structure.
U.S. Pat. No. 4,981,820 discloses a method in which select silicone resins can be mixed with a solvent, a foaming agent such as the isocyanate capped polyoxyethylene polyol, and sometimes a curing agent for crosslinking the resin. The foaming agent is reacted to form a carrier foam with the resin disposed throughout the foam as a continuous separate phase. Solvent and excess water are removed from the foam by drying, and the resin is crosslinked after the foam forms so that the resin retains the foamed structure. After the resin has crosslinked, the carrier foam is removed by decomposition. The remaining foamed resin structure is heated in a non-oxidizing atmosphere to pyrolize the resin, and the pyrolizing resin densifies to form a cellular glass structure.
It is an object of this invention to provide a method for forming metallic porous bodies of molybdenum, molybdenum alloy, tungsten, tungsten alloy, or mixtures thereof.
It is an object of this invention to provide a method for forming the metallic porous bodies that does not require the use of metal powder binders or fluxing agents.